Base Antennas for P25 Monitoring

[joesheets]

I am looking at installing a high gain antenna to monitor area P25 systems. I am very close to the NC VIPER tower in Southern Pines, so no problem there.
What I am trying to get to is the VIPER tower in Fayetteville, which is 30 miles direct (700 mhz) and Ft Bragg system (380 mhz), which is 27 miles direct.
I am thinking the best option is yagis pointed towards those locations. I have a multiband discone at 20 ft and get some decode on the Ft Bragg system but nothing on the Fayetteville system. We are in pretty flat area. I am at 500' msl and fayetteville and Ft Bragg are about 150'. Also looking for best coax for about 80' run.
Thoughts?
J

 

[buddrousa]

Depending on what your coax is now upgrading to Times Microwave LMR400 or Belding 9913 not the cheap copies you could obtain gain there.
Also multiple scanners and beams on good coax could help also. There are good reasons I run 16 plus scanners at home sharing the same antenna with a project of a 50 foot Rohn 25G tower with 150 beam a 460 beam and a 800 beam going up with Times Microwave LMR400 runs.

 

[joesheets]

Ok. I will look into upgrading the coax. I don't want to break the bank tho!
What about RG11? Maybe not as good but according to the charts at 800mhz, it has 4.4 DBi loss at 100' compared to 3.6 DBi with LMR400. And its about half the price.

 

[buddrousa]

Here is a link to a chart

Coaxial Cable Attenuation Chart

www.universal-radio.com

 

[joesheets]

That chart and the calculator here: Coax Calculator ,explains the power loss on transmit.
Is that the same a an attenuation of a received signal?

 

[buddrousa]

Joe you have a good calculator I was just pointing you away from the CHEAP KNOCK OFF LMR400 sold on EBAY

 

[joesheets]

Ok. Thanks.

 

[GMB951]

The Yagi is what I use and I get 5 or 6 Towers from front and back

 

[joesheets]

What yagi are you using? Homebrew?

 

[devicelab]

What yagi are you using? Homebrew?

The Wilson yagi does a respectable job for the price: Amazon.com: Wilson Electronics 301111 Yagi Antenna: Home Audio & Theater

It won't help for 380 Mhz; however, this may receive 380Mhz just fine: HYS UHF Repeater Base Directional Antenna Yagi 400-470MHz 5 Elements 9 dBi Gain | eBay

 

[joesheets]

Thanks. Just ordered the Wilson. I actually get the Ft Bragg system pretty well with a 1/4 wave ground plane I built.

 

[devicelab]

Thanks. Just ordered the Wilson. I actually get the Ft Bragg system pretty well with a 1/4 wave ground plane I built.

You're welcome. As Budd said earlier go with LMR400 -- you can't go wrong. I picked up the Wilson 100ft length recently and it works just fine.

Amazon.com: Wilson Electronics 100 ft. Black WILSON-400 Ultra Low Loss Coax Cable (N-Male to NMale)

Buy Wilson Electronics 100 ft. Black WILSON-400 Ultra Low Loss Coax Cable (N-Male to NMale): Digital Coaxial Cables - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Times Microwave may be the standard but it's also (at least) 2x the cost.

EDIT: Okay you can get TM LMR400 from HRO @ $1/ft but you'll have to install your own connectors:

You are being redirected...

 

[joesheets]

Ok. I will check them out.
How high do you have the yagi?

 

[devicelab]

How high do you have the yagi?

Mine is at 20ft above ground but the higher the better.

 

[joesheets]

Ok. Thats what I have available at the moment (2 connected fence-top rails). I want to have it somewhat "portable" to move it around the lot to get to more towers.

 

[tvengr]

Stay away from RG11. That is 75 ohm cable. You should keep everything at a 50 ohm impedance. 75 ohm cable is used for TV antennas and cable TV.

 

[joesheets]

I have Ordered LMR400.

 

[JoshuaHufford]

I have Ordered LMR400.

Good choice. Do it right the first time.

Wish I had all the wasted time and money back that I've lost learning this lesson in life the hard way.

 

[Robertolson]

Make sure it’s Original (Times Microwave) LMR 400......... Not a China knock off you find on EBay / Amazon ....must have .....for High Frequency monitoring

 

[joesheets]

I got the Wilson version.